The present invention relates to a new and improved construction of a roller assembly capable of being arranged in the guide path of a continuous casting machine for the casting of sectional members, especially beam blanks, typically for instance I-shaped sections.
It is already known in this particular field of technology to support a beam blank in the guide path or the secondary cooling zone, respectively, of a continuous casting machine or installation, especially for casting steel, by positioning a plurality of rollers around the periphery of the beam blank section. With such prior art roller assembly construction there are provided lateral rollers having their rotational axes in a vertical plane and abuttingly engaging the outer flange faces of the casting. Further, radially extending web rollers are in abutting contact with the web part of the casting, and each flange tip of the casting is supported by a radially extending flange tip roller. This construction is both problematic and cumbersome owing to the multitude of bearing supports which are required. The alignment and assembly of each individual roller also requires a great deal of time. Additionally, the supported length of the web part or portion which extends transversely with respect to the direction of travel of the beam blank must be restricted because of the space which is needed to accommodate the bearing supports at either end of the web rollers. Hence, the unsupported sections of the web part oftentimes have a defective surface finish, leading to possible rejection of the finished product.
Now in order to overcome these difficulties, it has been further proposed to replace at each radial side of the casting one web roller and two flange tip rollers by a single roller unit which is supported at either end. The intermediate cylindrical portion of this roller unit has a larger diameter than the side cylindrical portions. The middle or intermediate cylindrical portion supports the web part or portion of the beam blank, whereas the side portions support its flange tips. While this modified construction of prior art roller assembly can be considered to constitute an improvement, nonetheless the life-span of such roller units is limited due to the difference in the peripheral speed of the intermediate or middle portion of the roller unit in comparison to that of the side portions of such roller unit. Moreover, due to this difference in peripheral speed or velocity, these roller units can cause skin drag on the still vulnerable solidified skin of the beam blank or casting, thereby causing metal breakouts and/or other surface defects.